CN106715358B - Method for expanding sand grains type raw material - Google Patents

Abstract

The present invention relates to a method for expanding a raw material (1) in the form of sand, which is passed through a substantially vertical heated shaft ( 3) Drop downwards and to the dosing element (6), which can be connected to the substantially vertical shaft (3) and the conveying line (7). In order to prevent pressure fluctuations from the conveying line (7) in the area of the shaft (3), a dosing element (6) is attached between the shaft and the conveying line (7), from the shaft (3) ) the amount of particles ( 5 ) transferred to the conveying line ( 7 ) is adjusted via means ( 9 ) for adjustment so as to form the defined material aggregation of the particles ( 5 ) as the dosing element ( 6 ) The cache decouples the axial flow (4) from the transport flow (8).

Description

Method for expanding grit-type raw material

technical field

The present invention relates to a method for expanding a raw material in the form of grit, wherein the raw material is dropped downwards and onto a dosing element through a substantially vertical heated shaft provided with means for heating and with an axial flow prevailing. The elements can be connected to substantially vertical shafts and conveyor lines.

current technology

WO 2013/053635 A1 discloses a method for producing expanded particles from a grit-type raw material, wherein the aim is to adjust the closed surface of the expanded particles in a controlled manner so that the expanded particles have no or little water absorption. In addition, the possibility is offered to influence in particular the surface structure of the expanded particles and thus the roughness. To this end, this document proposes to provide a plurality of independently controllable heating elements arranged along the falling portion of the grit-type raw material and to perform temperature detection along the falling portion, wherein the heating elements are controlled according to the temperature detected under the area where the expansion process takes place. The removal of the expanding particles from the lower end of the falling part is ensured by the pneumatic conveying line to which the falling part leads.

As a result of the vertical alignment of the shafts and as a result of the additional introduction or extraction of process gases accompanying the expansion process, a flow of raw material in the form of sand occurs within the shafts. In particular, the formation of a near-wall, upwardly directed boundary layer flow has a positive effect on the various expansion steps, since this boundary layer flow prevents any baking of the grit-type raw material on the shaft wall. If the expansion axis is closed towards the top, a central, downwardly oriented core flow is created in addition to the upwardly oriented boundary layer flow. This core flow prevents some of the above-mentioned boundary layer flow, thus leading to baked deposits. The effect of the core flow can be reduced by drawing process gas from/injecting process gas into the head region of the shaft, as heretofore known.

However, as a result of the direct connection of the shaft to the pneumatic conveying line, the cleaning cycle of the filter in the conveying line may cause, generate pressure fluctuations that are transmitted directly to the air in the shaft. As a result, a transverse flow is generated in the region of the shaft, which interferes with the positive effect of the boundary-layer flow, thus giving rise to dry deposits, which lead to a serious deterioration of the quality of the expansion process and can only be passed through the complicated process when the process is stopped. Maintenance measures are eliminated.

Therefore, the non-uniform expansion process and the formation of baked deposits on the shaft walls can be regarded as disadvantages of the prior art, which occur as a result of, for example, transverse flow caused by pressure fluctuations in the subsequent pneumatic conveying line. Known extraction of process gas from/injection of process gas into the head region of the shaft does not prevent this effect.

SUMMARY OF THE INVENTION

The objective formulation that forms the basis of the present invention is to provide a method for producing expanded particles from a grit-type raw material and a dosing element for connecting a shaft to a conveying line, without the disadvantages described and ensuring that pressure fluctuations from the conveying line do not affect the quality of the expanded particles . The method should ensure trouble-free, low-maintenance operation. The dosing element should be characterized by a simple and reliable design. Furthermore, it should be possible to retrofit existing systems with the present invention without significant expenditure.

This objective is achieved by the method initially mentioned, whereby a dosing element is attached between the shaft and the conveying line, the amount of particles transferred from the shaft to the conveying line being adjusted via means for adjusting A defined accumulation of material such that the particles are formed as a buffer in the dosing element that decouples the axial flow from the transport flow.

The invention is based on the fact that, as a result of the accumulation of material that can be formed by simple means, possibly by accumulation of particles falling downwards, pressure conditions can be created in the region above the accumulation of material, which pressure conditions are in normal operation No longer affected by pressure fluctuations in the conveyor line. It goes without saying that, as a result of the buildup of material forming, a complete hermetic sealing of the shaft with respect to the conveying line cannot be achieved, but the sealing effect is sufficient to prevent pressure fluctuations from being transmitted from the conveying flow to the axial flow.

By attaching means for adjustment, the height of the material accumulation can be specifically influenced and adjusted to the optimum value for the current process, which must not fall below the lower limit and must not exceed the upper limit.

As for the grit-type raw material, not only ore sand bound with water as a propellant (for example, perlite or blackstone sand) can be used. It may also include mineral dust mixed with a hydrous mineral binder, in which case the hydrous mineral binder acts as a propellant. In this case the expansion process can be carried out as follows: The ore dust consisting of relatively small sand particles having a diameter of eg 20 μm is formed by a binder into larger particles of eg 500 μm. At the critical temperature, the surface of the sand grains of the mineral dust becomes plastic and forms a closed surface of the larger grains or melts to form a closed surface of the larger grains. In this way, a reduction in surface energy or surface-to-volume ratio is obtained since the closed surface of a single larger grain is generally smaller than the sum of all surfaces of the individual sand grains of the mineral dust involved in forming this larger grain. At this point, larger grains are present, each with closed surfaces, wherein the grains comprise a mixture of ore dust and a hydrous mineral binder. Since the surfaces of these ore particles are plastic as before, the subsequent formation of water vapor can expand the larger particles. That is, aqueous mineral binders are used as propellants. Alternatively, the mineral dust can also be mixed with a propellant, wherein the propellant is mixed with a preferably aqueous mineral binder. For example _CaCO3 can be used as propellant. In this case, the expansion process can occur similar to the process described above: mine dust with a relatively small grit size (eg, 20 μm diameter) forms larger particles (eg, 500 μm diameter) with the propellant and mineral binder. After reaching the critical temperature, the sand surface of the mineral dust becomes plastic and forms a larger closed surface or melts to form a larger closed surface. The closed surfaces of the larger grains are plastic as before and are now capable of being expanded by the propellant. If the mineral binder is aqueous, it can act as an additional propellant. Thus, in a preferred embodiment of the method according to the invention it is proposed that the mineral material with propellant comprises mineral material bound with water and the water acts as the propellant or mineral dust mixed with an aqueous mineral binder acting as the propellant or Mineral dust mixed with a mineral mixed propellant binder, wherein the mineral binder preferably contains water and acts as an additional propellant. In order to be able to implement the given method as efficiently as possible, in addition to the shaft furnace, it is preferable to provide a plurality of heating zones with (independent of each other) controllable heating elements and intelligent regulation and control units. The heating element is preferably controlled as a function of the temperature measured along the furnace axis.

The method according to the invention can be configured, for example, like WO 2013/053635. The entire content of this application is therefore incorporated into this specification.

A preferred embodiment is characterized in that the accumulation of material acting as a buffer is designed such that at least a first section of the dosing element is completely filled with expanded particles from the shaft above a defined height. A feature of this type of cache is that it is particularly simple to generate. Expanding particles falling from the shaft are piled up until a certain height is reached, and the resulting accumulation of material acts as a buffer. The height of the material accumulation can for example be defined by the position of the measuring device, which is attached in the dosing element and detects the presence of the material accumulation. The position of the measuring device in the operating state of the dosing element corresponds to a certain height within the dosing element and thus also to a certain height of the subsequently existing material accumulation.

According to another preferred embodiment, the conveying flow is produced by means of a suction device. If the suction system is attached in particular at the end facing away from the dosing element, the conveying flow is obtained over the entire length of the conveying line in which other elements such as filter systems can be attached.

In another preferred embodiment, a separation device, preferably a cyclone, is arranged in the conveying line, by means of which the expanded particles are separated from the conveying stream. Since the expanded particles comprise the end product of the process, the concentrated removal from the conveying stream, in particular by means of a cyclone, is advantageous, since in this way a container such as a silo can be filled in a simple manner For further transport or further processing of said particles.

Yet another preferred embodiment provides that the bulk density of the particles is determined as a quality characteristic of the expansion process to subsequently adjust the means for heating or reduce the feed of raw materials. By continuously controlling the expanding particles, such a procedure allows conclusions to be drawn from the conditions in the shaft. If the bulk density differs significantly from the set standard parameters, it may be caused on the one hand by a different composition of the grit-type raw material, which can be compensated by modifying the temperature in the device for heating, or it can be caused by the inside of the shaft caused by drying deposits on it. If the latter happens, the feed of raw material can be reduced, preferably stopped completely, to enable maintenance work.

According to a further particularly preferred embodiment, the means for regulating increase or decrease the delivery volume of expanded particles in the delivery line by locally influencing the delivery flow in the dosing element. This adjustment of the delivery rate can be achieved without the need to move parts in contact with the expanded particles, thus resisting clogging. A reduction in the delivery volume causes an increase in the material accumulation, while the opposite happens when the delivery volume increases.

In a further particularly preferred embodiment, the height of the accumulation of the material in the dosing element is detected and this information is sent to the device for adjustment. As a result, the height of the material accumulation can be changed by affecting the delivery amount or the uneven feeding of raw material can be compensated so that the height of the material accumulation remains approximately constant.

According to yet another preferred embodiment, process air is drawn from the head region of the shaft to increase the portion of the axial flow directed to the head region thereby stabilizing the axial flow. As a result of this design, the positive effect of the absence of pressure fluctuations is combined with the reduction of the downwardly directed core flow, with the result that the flow conditions in the shaft can remain largely constant independently of external influences.

Yet another preferred embodiment of the present invention provides for blowing or sucking process air into the head region of the shaft to stabilize the portion of the axial flow directed to the head region. This offers another possibility for keeping the flow conditions in the shaft substantially constant and has a positive effect on the quality of the expanded particles as a result of simultaneously reducing pressure fluctuations from the conveying line.

The dosing element according to the invention is characterized in that it comprises a material container, which can be connected to the shaft via a shaft connection and has a longitudinal axis, a conveying part, which can be conveyed via a conveying part, and a device for adjustment. The connecting piece is connected to the conveying line, the means for conditioning being configured such that a material accumulation occurs in the area of the material container when particles enter the material container. The dosing element may be connected to the shaft by the shaft connection to allow expanded particles to enter the material container. Via the conveying section, the particles reach the conveying connection by which the dosing element can be connected to the conveying line to ensure removal of the expanded particles that have passed through the dosing element. The conveying volume through the dosing element is influenced by the means for regulating such that since more particles fall from the shaft into the material container than are removed from the dosing element via the conveying connection, The material thus accumulates in the material container. If the material accumulation has reached a certain defined height, the amount conveyed by the dosing element will approximately correspond to the amount of particles falling from the shaft to the material container.

The system according to the invention can be configured such that a substantially vertical heatable shaft is connected via the shaft connection to the material container provided with the dosing element of the means for adjusting the delivery volume, the delivery portion of the dosing element via the The delivery connection is connected to the pneumatic delivery line.

The initially formulated objective can thus be solved only by the quantitative element according to the invention, but also by the system according to the invention comprising the quantitative element. Thus, the invention also relates to a system for implementing the method according to the invention by means of a dosing element connected to a substantially vertical heatable shaft and a pneumatic conveying line, according to the invention it is proposed that said dosing element comprises a material container, a conveying part and a device for adjusting, the material container is connected to the shaft via a shaft connection and has a longitudinal axis, the conveying portion is connected to the conveying line via a conveying connection, the apparatus for adjusting is configured such that in Material accumulation occurs in the region of the material container as the particles enter the material container.

According to a preferred embodiment of the dosing element according to the invention or the system according to the invention, the conveying section is guided through the material container transversely to the longitudinal axis of the shaft. This connection of the conveying section and the material container is characterized in that no complicated construction is required. The material containers can be welded together, for example, from thin metal sheets, the dimensions of which must only be designed such that their dimensions are larger than the diameter of the conveying section.

In a further preferred embodiment of the dosing element according to the invention or the system according to the invention, the delivery part can be connected to the ambient atmosphere on the side opposite the delivery connection, with the result that the extraction system can be extracted Ambient air to create a conveying flow and transport it through the conveying line.

According to a further particularly preferred embodiment of the dosing system according to the invention or the system according to the invention, on the side opposite the shaft connection, the delivery part has at least one opening to ensure the transfer of the expanded particles to the in the conveying section. This design ensures that the particles enter the conveying section only by suction of the conveying flow and that the particles cover the longest possible path before reaching the at least one opening.

A further particularly preferred embodiment of the dosing system according to the invention or the system according to the invention provides that a measuring device is attached in the region of the material container, by means of which the height of the material accumulation can be detected, And the measuring device is coupled to means for adjusting the delivery volume. As a result, the delivery amount can be increased or decreased via the means for regulating depending on the height of the accumulation of the material. If the height falls below the minimum height, the delivery rate is throttled, and if the maximum height is exceeded, the delivery rate is increased.

According to a further particularly preferred embodiment of the dosing system according to the invention or the system according to the invention, the device for adjusting the delivery volume is designed as an inner tube which is arranged inside the delivery section and a butterfly valve located in the inner tube. As a result of this simple design of the device for adjustment, the delivery volume can be adjusted by adjusting the valve. The inner tube is preferably of the same length as the delivery section and is connected to the atmosphere on the same side as the delivery section in the operating state so that ambient air can also be drawn through the inner tube. In addition, it is advantageous to attach the inner tube concentrically to the delivery portion to achieve a uniform suction effect.

In a further particularly preferred embodiment of the dosing system according to the invention or the system according to the invention, the butterfly valve is configured such that it can be closed on the one hand so that when the measuring device detects an excess of the material accumulation The defined height of the inner tube reduces the cross-section of the inner tube where the flow takes place to increase the delivery volume and thereby reduce the height at which the material accumulates, and on the other hand can be opened so that the measuring device detects a drop to the material Below the defined height of accumulation, the cross-section of the inner tube where flow occurs is increased to reduce the amount of delivery and thereby increase the height at which the material accumulates. Since the butterfly valve has the same diameter as the inner tube, the cross section where the flow occurs can be adjusted. If the butterfly valve is perpendicular to the longitudinal axis of the inner tube, there is no cross section where flow occurs and a strong suction force is created between the inner tube and the inner surface of the conveying part, with the result that more expanded particles are removed from the The material container is sucked in. If the butterfly valve is parallel to the longitudinal axis of the inner tube, the same suction effect prevails over the entire cross-section of the delivery section and only a small amount of particles enter the delivery section.

Description of drawings

The following is a detailed description of the method according to the invention and the apparatus according to the invention. In the attached image:

Figure 1 shows a schematic diagram of a system according to the invention;

Figure 2 shows a detailed view of a dosing element according to the present invention; and

FIG. 3 shows a cross-sectional view of the dosing element according to the invention along the line AA in FIG. 2 .

Detailed ways

Figure 1 shows a system for expanding grit-type raw material 1 . In this case, the raw material 1 is dropped by a vertical shaft 3, which can be heated by the device 2 for heating, in this embodiment a plurality of resistance heaters 2 are used. Raw material is fed into the head region 16 of the shaft 3 . Since the resistance heaters 2 can be controlled individually, a specific temperature distribution can be created along the axis 3 . As a result of the thermal radiation acting on the raw material 1 from the shaft 3 , the raw material 1 expands to form expanded particles 5 . Due to the heated walls of the shaft 3 and the consequent process air 18 an axial flow 4 is created in the shaft 3 consisting of a near-wall boundary laminar flow towards the head region 16 and a central flow towards the shaft connection 20 Core stream composition.

An additional air extraction device 17 is provided in the head region 16 of the shaft 3 from which the process air 18 is extracted in order to improve the axial flow 4 . In addition, a control loop 30 is coupled to the additional extraction device 17, regulating the ratio of the process air 18 extracted to the ambient air drawn in. Similarly, process air can be blown into the head region 16 by this additional air extraction device 17 or another device not shown here to stabilize the axial flow 4 .

A dosing element 6 is located at the lower end of the shaft 3 and regulates the amount of particles 5 conveyed from the shaft 3 to the pneumatic conveying line 7 . The dosing element 6 has a shaft connection 20 at the connection point with the shaft 3 and a conveying connection 23 at the connection point with the conveying line 7 . Similarly, a measuring device 15 is mounted on the part of the dosing element 6 adjoining the shaft 3, the measurement data of which is used to adjust the delivery volume.

A suction device 12 , preferably designed as a fan, is installed at one end of a pneumatic conveying line 7 designed to communicate with the atmosphere for conveying the expanded particles 5 , drawing ambient air from the other end of the conveying line 7 . Within this conveying line 7 is located a cyclone 13 from which the particles 5 are separated. A filter system 28 is located in the conveying line 7, preferably arranged between the cyclone 13 and the air extraction device 12, from which small particles are separated. By measuring the differential pressure by means of an additional measuring device 29, the delivery volume of the suction device 12 is controlled so that the flow rate in the delivery line 7 remains constant even if the filter system 28 is contaminated.

Figure 1 shows that in this embodiment a weighing device 14 is additionally provided, which is arranged downstream of the cyclone 13 with respect to the flow of particles 5 and can be used to determine the weight and thus the volume of the separated expanded particles 5 density. From this measurement, the quality of the expansion process can be assessed, thereby reducing the feed of the raw material 1 , preferably stopping it completely, or increasing the output of the resistance heater 2 in a specific area of the shaft 3 . Alternative embodiments of the present invention do not provide the weighing device 14 so that the expanded particles 5 are introduced directly from the cyclone 13 into the vessel (preferably, a silo).

2 and 3 now show detailed views of the dosing element 6 . FIG. 3 shows one of the main functions of the dosing element 6 : forming a material accumulation 10 . The expanded particles 5 fall from the shaft 3 via the shaft connection 20 ( FIG. 1 ) into the first part of the dosing element, namely the material container 19 , which has a longitudinal axis 21 . Since the amount of particles 5 coming from the shaft in the first process step is higher than the amount of particles 5 entering the conveying line through the dosing element 6, the material container 19 is filled with expanded particles 5 to form a material accumulation 10 which is at least filled with material The first section 11 of the container 19 . In this way, the space above the material accumulation 10 in the operating state (in particular the shaft 3 ) can be decoupled in terms of pressure technology from the space in the operating state downstream of the material container 19 (in particular the conveying line 7 ), so that Pressure fluctuations in the conveyor line 7 do not affect the axial flow 4 . The material container 19 is designed such that it has at least the same cross-section as the shaft 3 in the region of the shaft connection 20, preferably the entire upper region of the material container 19 has the same cross-section as the shaft 3, in particular rectangular.

Figure 2 shows that the conveying portion 22, which preferably has a circular cross-section, is guided through the lower region of the material container 19, the conveying portion 22 preferably has a larger cross-section than the shaft 3, and the maximum diameter of the conveying portion 22 is configured to be smaller than the material container 19 Minimum size inside. The distance between the outside of the conveying portion 22 and the inside of the material container 19 is a multiple of the desired maximum diameter of the particles of the expanded particles 5 known from process-related experience. Typically, the multiplication factor is in the range between 10-fold and 100-fold, preferably in the range between 20-fold and 40-fold. Typical particle diameters of the expanded particles 5 are in the range of 0.5 mm to 5 mm. For example, for a particle diameter of 2 mm and a factor of 30, a distance of 2 mm x 30 is obtained, ie 60 mm.

The material container 19 thus encapsulates at least a portion of the delivery portion 22 , preferably the entire delivery portion 22 . The delivery portion 22 is therefore preferably in contact with and against the base surface of the material container 19 . The conveying section is thereby guided transversely to the longitudinal axis 21 of the material container, which in this variant of the invention intersects the axis of the conveying section 22 at a certain point and the angle between the axes is 90°. Alternative embodiments of the present invention may also have different angles and off-axis. In order to ensure the transfer of the expanded particles 5 from the material container 19 to the delivery portion, at least one opening 24 is provided in the delivery portion 22 (Fig. 3). In this variant of the invention this at least one opening 24 is located on the opposite side of the conveying part 22 from the shaft connection 20 (in particular on both sides of the conveying part 22, here symmetrically about the longitudinal axis 21), ie in the operating state The middle is located on the lower side, wherein at least one opening 24 is preferably designed as a variety of slits. Alternative embodiments provide that at least one opening 24 has a rectangular, square or circular shape. In either case, the at least one opening 24 must be sized so that particles having the largest diameter known from experience with the process can still pass through the at least one opening 24 without clogging. Preferably the ratio between the particles and the diameter of the openings 24 is between 1:3 and 1:100, particularly preferably between 1:5 and 1:50, in particular between 1:5 and 1:25. For example, for a particle diameter of 2 mm and a ratio of 1:5, the diameter of the opening 24 is obtained as 2 mm x 5 = 10 mm.

The means 9 for adjusting the delivery volume are located inside the delivery part 22 , in this variant the means 9 for regulating the delivery volume are designed as an inner tube 25 with a butterfly valve 26 . In this case, the maximum diameter of the inner tube 25 is preferably circular like the delivery portion 22, smaller than the minimum diameter of the delivery portion 22, and the two elements are arranged concentrically. By varying the cross-section and location of the inner tube 25, many alternative designs are possible. The inner tube 25, similar to the delivery section 22 and thus to the delivery line 7, is also connected to the atmosphere on the side opposite the delivery connection 23, whereby ambient air can be drawn through all the aforementioned elements.

The butterfly valve 26 is provided inside the inner tube 25 and is preferably configured as a circular plate having a diameter that allows the inner tube 25 to be closed. This butterfly valve 26 is rotatably mounted so that it is pivotable about an axis perpendicular to the axis of the inner tube 25 . This pivoting can take place in the region between a first position where the butterfly valve 26 is parallel to the longitudinal axis of the delivery portion 22 and a second position where the butterfly valve 26 is perpendicular to the longitudinal axis of the delivery portion 22 .

The same conveying flow 8 produced in the conveying line 7 by the air extraction device 12 ( FIG. 1 ) predominates in the conveying section 22 . By means of this conveying flow 8 , the particles 5 are conveyed from the material container 19 via the at least one opening 24 to the conveying section 22 and further to the conveying line 7 .

If the measuring device 15 ( FIG. 1 ), which monitors the height of the material accumulation 10 in the upper part of the material container 19 in the operating state, detects that the height of the material accumulation 10 is too low, the butterfly valve 26 is opened, ie the first direction towards the butterfly valve 26 is Pivot in the direction of a position. As a result, the cross-section 27 in which the flow occurs when the second position is reached has the same size as the diameter of the inner tube 25 , and the conveying flow 8 of the same flow rate dominates the entire cross-section of the conveying portion 22 . As a result, a small amount of particles 5 is transferred from the material container 19 into the conveying section 22 and the height of the material accumulation 10 increases.

If the measuring device 15 ( FIG. 1 ) now detects that the height of the material accumulation 10 is too high, the butterfly valve 26 is closed, ie pivoted in the direction of the second position of the butterfly valve 26 . As a result, the cross-section 27 in which the flow occurs is minimal when reaching the first position, preferably completely closed, so that the flow velocity in the annular region between the inner tube 25 and the inside of the conveying section 22 becomes high, resulting in a strong suction and a large number of particles 5 from The material container 19 is transferred to the conveying section and the height of the material accumulation 10 sinks.

This ensures that the height of the material accumulation 10 can always be kept within a defined range to maintain the effect of decoupling the axial flow 4 from the delivery flow 5 .

In this case, the minimum height of the material accumulation 10 is determined by the at least one opening 24 which must be covered by said minimum height. The actual height of the material accumulation 10 created during operation is determined by the distance between the measuring device 15 and the conveying part 22, wherein said distance is preferably between 1 cm and 15 cm. The measuring device 15 (or its detector) should therefore preferably be attached only slightly above the outer diameter of the annular gap, where the air for suction in the expanding particles 5 (between the inner tube 25 and the inside of the conveying part 22 ) should be attached ) flows through the annular gap.

Reference list

1 Sand-type raw materials

2 Device for heating (resistance heater)

3 axes

4 Axial flow

5 Expanding particles

6 Dosing element

7 Pneumatic conveyor line

8 Delivery stream

9 Devices for adjustment

10 material accumulation

11 First Section

13 Cyclone (separation equipment)

14 Weighing equipment

15 Measuring equipment

16 Head area

17 Additional extraction equipment

18 Process air

19 Material container

20 axis connection

21 Vertical axis

22 Conveying part

23 Conveyor connection

24 openings

25 inner tube

26 Butterfly valve

27 Sections of Streaming Send

28 filter system

29 Additional measuring equipment

30 Control loop

Claims (17)

CLAIMS 1. A method for expanding a raw material (1) in the form of sand grains, said raw material (1) passing through a vertical heated shaft (3) provided with means (2) for heating and with an axial flow (4) prevailing Falling downwards, the raw material (1) expands into expanded particles (5) as a result of heat transfer in the shaft (3) and the resulting expanded particles (5) enter a pneumatic conveying line with conveying flow (8) (7) For further transport, characterized in that a dosing element (6) is attached between the shaft (3) and the pneumatic conveying line (7), transferring from the shaft (3) to the pneumatic conveying line (7) The amount of expanded particles ( 5 ) of the delivery line ( 7 ) is adjusted via means ( 9 ) for adjustment such that a defined accumulation ( 10 ) of material of said expanded particles ( 5 ) is formed as said dosing element ( 6 ) The buffer in the buffer decouples the axial flow (4) and the transport flow (8). 2. The method according to claim 1, characterized in that the material accumulation (10) acting as a buffer is designed such that at least a first section (11) of the dosing element (6) is completely filled with more than A defined height of expanded particles (5) from the shaft (3). 3. The method according to claim 1 or 2, characterized in that the conveying flow (8) is produced by means of a suction device (12). 4. The method according to claim 1 or 2, characterized in that a separation device is provided in the pneumatic conveying line (7), through which the expanded particles (5) are removed from the conveying flow ( 8) Separation. 5. The method according to claim 4, characterized in that the separation device is a cyclone (13). 6. Method according to claim 1 or 2, characterised in that the bulk density of the expanded particles (5) is determined as a quality characteristic of the expansion process to subsequently adjust the means (2) for heating or to reduce the raw material (1) feed. 7. The method according to claim 1 or 2, characterized in that the device (9) for regulating increases or decreases the amount of the conveying flow (8) by locally influencing the delivery flow (8) in the dosing element (6). The conveying amount of the expanded particles (5) in the pneumatic conveying line (7). 8. The method according to claim 1 or 2, characterized in that the height of the material accumulation (10) in the dosing element (6) is detected and this information is sent to the device for adjustment ( 9). 9. Method according to claim 1 or 2, characterised in that process air (18) is extracted from the head region (16) of the shaft (3) to increase the amount of air thereby stabilising the axial flow (4) is directed to the portion of the head region (16). 10. Method according to claim 1 or 2, characterised in that process air (18) is blown or sucked into the head region of the shaft (3) to stabilize the direction of the axial flow (4) to part of the head region (16). 11. A system for carrying out the method according to any one of claims 1 to 10 by means of a quantitative element (6) connected with a vertical heatable shaft (3) and a pneumatic conveying line (7), wherein In that the dosing element ( 6 ) comprises a material container ( 19 ), a conveying part ( 22 ) and a device ( 9 ) for adjustment, the material container ( 19 ) being connected to the shaft via a shaft connection ( 20 ) (3) and having a longitudinal axis (21), said delivery portion (22) is connected to a pneumatic delivery line (7) via a delivery connection (23), said means for adjustment (9) is configured such that upon expansion A material accumulation (10) occurs in the region of the material container (19) as the particles (5) enter the material container (19). 12. System according to claim 11, characterized in that the conveying portion (22) is guided through the material container (19) transversely to the longitudinal axis (21) of the shaft (3). 13. A system according to claim 11 or 12, characterized in that the delivery part (22) is connectable to the ambient atmosphere on the side opposite the delivery connection (23). 14. System according to claim 11 or 12, characterized in that, on the side opposite the shaft connection (20), the delivery part (22) has at least one opening (24) to ensure that the expansion will be The particles (5) are transferred into the conveying section (22). 15. A system according to claim 11 or 12, characterized in that a measuring device (15) is attached in the area of the material container (19) by which the height of the material accumulation (10) can pass A device (15) is detected and said measuring device (15) is coupled to means (9) for adjusting the delivery volume. 16. System according to claim 11 or 12, characterized in that the means (9) for adjusting the delivery volume are designed as an inner tube (25) arranged in the delivery section (22) and the butterfly valve (26) is located in the inner tube (25). 17. System according to claim 16, characterised in that the butterfly valve (26) is configured such that it can be closed on the one hand whereby an excess of the material accumulation (10) is detected at the measuring device (15) ) to reduce the cross-section (27) of the inner tube (25) where the flow takes place to increase the conveyance and thus reduce the height of the material accumulation (10), on the other hand can be opened and thus Said measuring device (15) increases the cross-section (27) of said inner tube (25) where flow occurs when it detects a drop below a defined height of said material accumulation (10) to reduce said delivery and thereby increase said Height of material accumulation (10).